(a) Field of the Invention
The present invention relates to a method for mass production of secondary metabolite using plant cell culture, and a culture media used therefor. More specifically, the present invention provides a method of producing secondary metabolite using plant cell culture by treating the culture media for plant cell culture with a saccharide mixture of at least two saccharides, to stimulate plant cell growth and increase the productivity of the secondary metabolite.
(b) Description of the Related Art
Plants are useful sources for producing a wide variety of secondary metabolites which are used as pharmaceuticals, pesticides, spices, pigments, food additives, cosmetics and the like. However, while the demands for secondary metabolites in various areas of industry are increasing, the supply of secondary metabolites produced by extraction from plants is limited. Therefore there have been efforts to commercially mass-produce secondary metabolites of plant origin by using plant cell culturing techniques (Stockigt et al., Plant Cell Tissue Org. Cult. 43: 914-920, 1995).
However, mass production of secondary metabolites through plant cell culture is still difficult due to problems such as instability of cultured cell lines, low productivity slow growth, scale-up cultivation and the like.
Various efforts have been made to try and overcome the low productivity in plant cell cultures, and they include the following methods: 1) adjustment of nutrient sources in the media such as addition of sucrose, nitrate salts, phosphate salts, growth regulators, and precursors; 2) optimization of the culture environments such as temperature, lighting, pH of the medium, shaking and aeration conditions; 3) treatment with elicitors to enhance productivity; 4) permeabilization of cell membranes and two-phase culture for effective recovery of secondary metabolites; and 5) metabolic engineering which enhances productivity of secondary metabolites by modifying genes involved in the biosynthesis of secondary metabolites or introduction of exogenous genes.
However, these trials were only effective for particular plant cells or secondary metabolites, and a method that can be generally applied to most plant cell cultures and secondary metabolites has not yet been established.
In general, the plant cell is cultured in an enriched culture media including various nutrients required for cell growth. The productivity of the secondary metabolite can be increased by controlling the nutrients, which are saccharides, nitrates, phosphates, growth regulators, and precursors required for producing the secondary metabolite, etc.
A carbon source is required for supplying the carbohydrate for the plant tissue culture or cell culture. Sucrose and glucose are most commonly used as a carbon source. In addition, fructose, lactose, maltose, galactose, and starch are used. Sorbitol is good for culturing a plant cell derived from a plant belonging to Rosaceae and apple tree, fructose is used for culturing apple rootstock M9 and Dedrobium, and glucose is suitable for wheat anther culture. Sucrose is generally used in a concentration of 2-3%, and can be used at a concentration of 5-12% in some cases. Glucose is used widely for culturing a plant cell of monocotyledon plant (Plant tissue culture and technique, HyangMunSa, 1987).
The preferred carbon sources vary depending on the species of plant, or the kind of cultured tissues or cells in plant cultures. Especially, in the case of the plant cell culture for production of secondary metabolites, the cell growth and the productivity of the secondary metabolites are affected by the carbon source.
There have been many attempts to produce plant cell-originated secondary metabolites on a large scale using plant cell culture techniques. However, there has been no report on a method for mass production of the secondary metabolites by use of a saccharide mixture as a carbon source for culture, which can be widely and generally applied to most plant cell culture and secondary metabolite production.